Velo Vitality stock Honjo in the UK now, but they are quite pricey.
I had the VO guards for a while, they were good but I also cracked the rear one, fit was ok but not perfect due to the long campag style dropouts and the need to occasionally remove the wheel without unbolting the guards entirely.
While the Honjo one are amazing, it's far from cheap.
The Velo Orange one is actually quite good, my girlfriend rode with her for quite some time (650b hammered one), and they're solid.
She destroyed her rear one on account of ignoring the rattling cause by loose bolt on the brake bridge, but apart from that, it's flawless.
Only nag is that the front is a little short, so a mudflap is advisable (Brompton's own is a great classic size and shape).